Dual-motion rotation and retraction system for minimizing muscle damage in spinal surgery

ABSTRACT

A dual-motion rotation and retraction system for forming a pathway to a patient&#39;s intervertebral disc space includes a dilator, retractable dual-blade assembly, and dual-motion retractor. The dilator may feature a narrow rectangular, elliptical, or elongated configuration body for insertion parallel to the fibers of the psoas muscle, including an angle of 0 to 90 degrees to the patient&#39;s spine. The dual-blade assembly includes opposing blade subassemblies, each having a blade bordered by adjustable wings, along with built-in lighting and video capabilities. The dual-blade assembly may be passed over the dilator at the insertion orientation. The dual-motion retractor may be disposed about the dual-blade assembly and dilator and employed to both rotate the dual-blade assembly and the dilator 0 to 90 degrees to a final rotated orientation parallel to the intervertebral disc space and to retract the opposing blade subassemblies away from one another to create the surgical pathway. Other embodiments are also disclosed.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

The application is a continuation-in-part of pending prior U.S. patentapplication Ser. No. 17/158,155, filed Jan. 26, 2021 by EdwardRustamzadeh for “LATERAL RETRACTOR SYSTEM FOR MINIMIZING MUSCLE DAMAGEIN SPINAL SURGERY,” which is a continuation-in-part of prior U.S. patentapplication Ser. No. 16/988,901, filed Aug. 10, 2020 by EdwardRustamzadeh for “LATERAL RETRACTOR SYSTEM FOR MINIMIZING MUSCLE DAMAGEIN SPINAL SURGERY” and issued as U.S. Pat. No. 10,925,593 on Feb. 23,2021, which is a continuation-in-part of prior U.S. patent applicationSer. No. 16/533,368, filed Aug. 6, 2019 by Edward Rustamzadeh for“LATERAL RETRACTOR SYSTEM FOR MINIMIZING MUSCLE DAMAGE IN SPINALSURGERY” and issued as U.S. Pat. No. 10,799,230 on Oct. 13, 2020, whichis a continuation of prior U.S. patent application Ser. No. 16/356,494,filed Mar. 18, 2019 by Edward Rustamzadeh for “LATERAL RETRACTOR SYSTEMFOR MINIMIZING MUSCLE DAMAGE IN SPINAL SURGERY” and issued as U.S. Pat.No. 10,426,452 on Oct. 1, 2019, which is a divisional of prior U.S.patent application Ser. No. 16/273,322, filed Feb. 12, 2019 by EdwardRustamzadeh for “LATERAL RETRACTOR SYSTEM FOR MINIMIZING MUSCLE DAMAGEIN SPINAL SURGERY” and issued as U.S. Pat. No. 10,363,023 on Jul. 30,2019, all of which patent applications are incorporated herein byreference.

BACKGROUND

The spine is a flexible column formed of a plurality of bones calledvertebrae. The vertebrae are hollow and piled one upon the other,forming a strong hollow column for support of the cranium and trunk. Thehollow core of the spine houses and protects the nerves of the spinalcord. The different vertebrae are connected to one another by means ofarticular processes and intervertebral, fibrocartilaginous bodies, orspinal discs. Various spinal disorders may cause the spine to becomemisaligned, curved, and/or twisted or result in fractured and/orcompressed vertebrae. It is often necessary to surgically correct thesespinal disorders.

The spine includes seven cervical (neck) vertebrae, twelve thoracic(chest) vertebrae, five lumbar (lower back) vertebrae, and the fusedvertebrae in the sacrum and coccyx that help to form the hip region.While the shapes of individual vertebrae differ among these regions,each is essentially a short hollow shaft containing the bundle of nervesknown as the spinal cord. Individual nerves, such as those carryingmessages to the arms or legs, enter and exit the spinal cord throughgaps between vertebrae.

The spinal discs act as shock absorbers, cushioning the spine, andpreventing individual bones from contacting each other. Discs also helpto hold the vertebrae together. The weight of the upper body istransferred through the spine to the hips and the legs. The spine isheld upright through the work of the back muscles, which are attached tothe vertebrae.

A number of approaches, systems, and apparatuses have been devised toaccomplish a variety of surgical interventions in association with thespine. These approaches enable a surgeon to place instrumentation andimplantable apparatuses related to discectomy, laminectomy, spinalfusion, vertebral body replacement and other procedures intended toaddress pathologies of the spine. The variety of surgical approaches tothe spine have a number of advantages and drawbacks such that no oneperfect approach exists. A surgeon often chooses one surgical approachto the spine from a multitude of options dependent on the relevantanatomy, pathology, and a comparison of the advantages and drawbacks ofthe variety of approaches relevant to a particular patient.

A common surgical approach to the spine is the lateral approach, which,in general, requires a surgeon to access the spine by creating asurgical pathway through the side of the patient's body through thepsoas muscle, or anterior to the psoas muscle, to an intervertebral discspace where it is possible to dock onto the lateral lumbar disc.Variants of the lateral approach are commonly referred to as the “directlateral” approach in association with the “DLIF” procedure, the “extremelateral” approach in association with the “XLIF” procedure, the “obliquelumbar” approach in association with the “OLIF” procedure, and the“anterior lumbar” approach in association with the “ALIF” procedure.

A common problem associated with the lateral surgical approach includesa significant risk of damage to the musculature surrounding the spine.FIGS. 1A-1B illustrates a partial view of a spine 100 comprised ofsequential vertebrae 109, each separated by intervertebral disc space110, with an attached psoas muscle group 102 (including the psoas minorand psoas major). As shown, the psoas muscle 102 runs generally in acranial-caudal direction with muscle fibers attached diagonally or at anapproximate 45-degree angle to the spine 100. FIGS. 2A-2B illustrate anexemplary lateral approach to the spine. In typical lateral approaches,after making an incision in the psoas muscle 102, the surgeon places anumber of sequential circular dilators 104 _(1-n), each larger indiameter, on the desired pathway to the spine 100 through the psoasmuscle 102 to dilate the surgical site radially away from the initialincision site or K-wire insertion point. This dilation process can leadto compression of muscle, nerves, and blood supplies adjacent to thevertebral body, which can lead to ipsilateral upper thigh pain, hipflexor weakness that causes difficulty in walking and/or stair climbing,and muscle atrophy that follows from muscle injury.

After the series of circular dilators are forced into the muscle tissue,a multi-bladed or tubular retractor apparatus 106 may be placed over thefinal dilator 104 _(n). The retractor is then retracted radially toseparate the psoas muscle and other soft tissues. A common problemassociated with this type of lateral procedure is that soft tissues,including the musculature and nerves surrounding the spine, becomecrushed and/or trapped near the distal end of the retractor's bladeswhen the retractor is passed over the final dilator, a problem oftenreferred to as “trappage,” graphically depicted in FIG. 3.

In order for the surgeon to clear the surgical pathway to the discspace, or to “see” the disc space, the surgeon must cauterize and cutthe muscle that is caught inside the retractor, effectively performing amuscle biopsy each time the surgeon performs an XLIF, DLIF, OLIFprocedure. Beyond undesired muscular damage to the patient, thisapproach requires additional effort for the surgeon to utilize a cauteryor similar device to remove the trapped soft tissues from between thedistal end of the retractor and the vertebral bodies prior to completingaccess to the spine.

Oftentimes the resulting damage and trauma to the soft tissue resultingfrom trappage and removal of psoas muscle tissue with a cautery causeslasting problems for a patient. For instance, a patient who experiencestrappage during surgery will often have ipsilateral upper thigh pain andleg weakness. Such pain and leg weakness occurs due to the linkage ofthe psoas to the lower body, as the psoas muscle connects to the femur.Thus, damage to the psoas will generally manifest in lower bodydiscomfort, including pain and weakness in the leg.

Another problem associated with existing lateral surgical approaches tothe spine is nerve damage. The lumbar plexus is a web of nerves (anervous plexus) in the lumbar region of the body which forms part of thelarger lumbosacral plexus. The lumbar plexus in particular is oftendamaged as a direct result of surgical intervention utilizing thelateral approach to the spine. The nerves associated with the lumbarplexus can experience indirect nerve injury as a result of over-dilationor over-retraction of apparatuses utilized to accomplish lateral accessto the spine. They also can experience direct nerve injury as a resultof direct trauma caused by impingement from the instrumentation utilizedduring the surgical intervention in association with the lateralapproach to the spine, as in the case of trappage, discussed above. Suchindirect and direct nerve damage can cause numbness in part or all ofthe leg and can lead to indirect muscle atrophy. A recent meta-analysisreview of 24 published articles indicates that the lateral approach isassociated with up to a 60.7% complication rate. Gammal, Isaac D, et.al, Systemic Review of Thigh Symptoms after Lateral Transpsoas InterbodyFusion for Adult Patients with Degenerative Lumbar Spine Disease,International Journal of Spine Surgery 9:62 (2015). The review furtherfound that the retractors resulted in 43% psoas muscle pain, 30.8% psoasmuscle weakness, and 23.9% nerve or plexus injury due to the inherentlyflawed design of existing commercially available retractors.

One existing method of neuromonitoring involves the insertion of anumber of epidural electrodes into the lumbar plexus. Stimulation of theelectrodes is used to trigger a response in the patient's nervestructures, and the resulting evoked potentials correspond to the neuralactivities of the nerve structures near the recording electrodes. Thepotentials may be recorded to detect reactions in the nervous systemthat may indicate a problem, including some type of impingement orencroachment of an instrument upon the nerve structures during aprocedure. This method, while providing information relating to a changein the behavior of the nerve structures nearby the inserted electrodes,does not directly correlate to a change in the behavior of the nervestructures in response to a nearby surgical instrument such as a dilatoror a retractor, and is therefore not optimal for identifying impingementfrom the instrumentation utilized during the surgical intervention.

In addition, existing dilators oftentimes incorporate a vertical wireconductor that extends through the outer wall of the dilator parallel tothe longitudinal axis of the apparatus, terminating in a pinpointelectrode at the distal end of the apparatus. The electrode maystimulate nearby nerve structures to assess for any impingement uponnerve or plexus. Because the vertical wire provides only a pinpointelectrode, the surgeon must manually rotate the apparatus through 360degrees to perform a full range of neuromonitoring for impingement uponall of the adjacent neurological structures surrounding the device: thefront and the back, superior and inferior. This additional step iscumbersome and presents challenges in achieving thoroughneuromonitoring. Moreover, because existing dilators with pinpointelectrodes require the surgeon to rotate the dilators to achieveneuromonitoring in 360 degrees, the dilators cannot perform a full rangeof monitoring once they are affixed. After fixation, only pinpointmonitoring is provided, and existing devices cannot provide continuous,real-time neuromonitoring throughout the procedure.

Existing retractor systems also present challenges in terms ofillumination and require a separate light source that attaches to thetop of the retractor. This separate device is cumbersome, physicallyinterfering and disruptive, and the limited ability to position thelight source oftentimes means that light reflects off of the retractorblades before returning to the surgeon's eyes, which leads to suboptimalvisualization of the surgical area.

Existing retractor systems also lack ease of adjustability and are notdesigned with an eye toward ergonomic use by the surgeon, who is forcedto hunch over the retractor apparatus during the course of the procedureto direct the surgical equipment as desired.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key aspects oressential aspects of the claimed subject matter. Moreover, this Summaryis not intended for use as an aid in determining the scope of theclaimed subject matter.

One embodiment provides a lateral retractor system for forming a lateralretractor system for forming a surgical pathway through, or anterior to,a plurality of psoas muscle fibers to a patient's intervertebral discspace, comprising a dilator including a conductive body extendingbetween a proximal end and a distal end; a first nonconductive layerdisposed upon an outer surface of the conductive body; a first activeneuromonitoring tip positioned at the distal end of the conductive bodyto a leading distal edge configured for insertion into theintervertebral disc space; and a first conductive electrical pathwayextending from a first conductive input surface at the proximal end ofthe conductive body, through the conductive body, and to the firstactive neuromonitoring tip such that an electrical signal applied to thefirst conductive input surface causes the first active neuromonitoringtip to simultaneously and continuously stimulate one or more nervestructures located adjacent to any portion of a circumference of thedistal end of the conductive body to assess for an encroachment of thedilator upon the one or more of the nerve structures.

Another embodiment provides a dilation system for minimizing damage to apatient's psoas muscle fibers when forming a surgical pathway to anintervertebral disc space of the patient's spine, the dilation systemhaving a dilator including a conductive body portion extending between aproximal end and distal end; a nonconductive layer disposed upon theconductive body portion; and a conductive neuromonitoring portionextending distally from the distal end of the conductive body portion toa leading distal edge configured for insertion between, or anterior to,the patient's psoas muscle fibers, wherein when an electrical dilatorstimulus is applied to the proximal end of the conductive body portion,the electrical dilator stimulus propagates through the conductive bodyportion to the conductive neuromonitoring portion such that theconductive neuromonitoring portion simultaneously stimulates one or morenerve structures located adjacent to any point about a circumference ofthe conductive neuromonitoring portion.

Yet another embodiment provides retraction system for forming a surgicalpathway through, or anterior to, a patient's psoas muscle to thepatient's intervertebral disc space, comprising a dilator for traversinga plurality of fibers of the patient's psoas muscle, the dilator havinga dilator body portion and a dilator neuromonitoring portion extendingdistally from the dilator body portion; a retractor having retractableblades configured to pass over the dilator, each of the retractableblades having a blade body portion and a blade neuromonitoring portionextending distally from the blade body portion, wherein the dilator andeach of the blades are conductive such that an electrical dilatorstimulus applied to the dilator body portion propagates to the dilatorneuromonitoring portion and an electrical blade stimulus applied to theblade body portion of each of the retractable blades propagates to eachof the blade neuromonitoring portions to simultaneously and continuouslystimulate one or more nerve structures located adjacent to any portionof a circumference of the dilator neuromonitoring portion and anyportion of a circumference of each of the blade neuromonitoring portionsto assess for an encroachment of the dilator and the dual-bladeretractor upon the one or more of the nerve structures; and aninsulative dilator nonconductive layer disposed upon the dilator bodyportion, and an insulative blade nonconductive layer disposed upon eachof the blade body portions.

Still another embodiment provides a dual-motion rotation and retractionsystem for minimizing damage to a patient's muscle fibers when forming asurgical pathway to the patient's spine. The dual-motion rotation andretraction system includes (1) a dilator comprising a narrow rectangular(which includes, but is not limited to, elliptical shapes) body definedby opposing flat surfaces that taper to a distal edge configured forinsertion adjacent to an intervertebral disc space at an insertionorientation in which the opposing flat surfaces of the dilator areparallel to a plurality of psoas muscle fibers and at an angle of 0degrees to less than 90 degrees to the patient's spine; (2) a dual-bladeassembly comprising a pair of opposing blade subassemblies, each of theopposing blade subassemblies having a blade with a planar inner surface,the dual-blade assembly configured for disposal about the dilator at theinsertion orientation such that the planar inner surface of the blade ofeach of the opposing blade subassemblies abuts one of the opposing flatsurfaces of the dilator; and (3) a dual-motion retractor configured fordisposal about and attachment to the dual-blade assembly, thedual-motion retractor comprising a rotative linking mechanism thatselectively transitions between: (a) a rotation mode that rotates thedual-blade assembly about a longitudinal center axis of the dilator fromthe insertion orientation to a rotated orientation in which the planarinner surface of each of the blades is parallel to the intervertebraldisc space; and (b) a retraction mode that retracts the opposing bladesubassemblies away from one another.

Yet another embodiment provides dual-motion retractor for (1) rotating adual-blade assembly having opposing blade subassemblies disposed aboutopposing flat surfaces of a dilator, and (2) retracting the opposingblade subassemblies away from the dilator to form a surgical pathwaythrough, or anterior to, a plurality of psoas muscle fibers to apatient's intervertebral disc space. The dual-motion retractor includes:(a) a retractor body having a disc support portion and a handle slideportion; (b) first and second opposing discs slidably coupled to thedisc support portion of the retractor body, the first and the secondopposing discs combining to define a blade-receiving aperture; (c) ahandle slidably coupled with the disc support portion of the retractorbody; and (d) a rotative linking mechanism operably coupled between thefirst and the second opposing discs and the handle, the rotative linkingmechanism configured to selectively switch between a rotation mode thatoperates to rotate the first and the second opposing discs and theblade-receiving aperture about a longitudinal center axis of theblade-receiving aperture and a retraction mode that operates to retractthe first and the second opposing discs from one another and expand theblade-receiving aperture.

An additional embodiment provides a method of forming a surgical pathwaythrough a side of a patient's body and through, or anterior to, a psoasmuscle to an intervertebral disc space. The method includes the steps of(1) providing a dilator having opposing flat surfaces that extend from aproximal end to a distal end; (2) providing a dual-blade assemblycomprising a pair of opposing blade subassemblies, each of the opposingblade subassemblies having a blade with a planar inner surface; (3)providing a dual-motion retractor, comprising: (a) a retractor bodyhaving a disc support portion and a handle slide portion; (b) a pair ofopposing discs slidably coupled to the disc support portion, the pair ofthe opposing discs combining to define a blade-receiving aperture; (c) ahandle slidably coupled with the handle slide portion; and (d) arotative linking mechanism operably coupled between the pair of theopposing discs and the handle. Additional steps include (4) using thedistal end of the dilator, traversing a plurality of fibers of the psoasmuscle, or re-positioning anterior to, until the dilator spans theintervertebral disc space at an insertion orientation in which theopposing flat surfaces of the dilator are disposed parallel to theplurality of the fibers of the psoas muscle and at an angle of 0 degreesto less than 90 degrees to the intervertebral disc space; (5) inserting,distally-to-proximally and at the insertion orientation, the dual-bladeassembly into the blade-receiving aperture of the dual-motion retractor;(6) securing each of the opposing blade subassemblies to respective onesof the pair of the opposing discs of the dual-motion retractor; (7)passing the dual-blade assembly, as secured to the dual-motionretractor, over the dilator at the insertion orientation such that theplanar inner surface of each of the blades abuts an opposing one of theopposing flat surfaces of the dilator; (8) first operating thedual-motion retractor in a rotation mode to rotate the dual-bladeassembly and the dilator about a longitudinal center axis of the dilatorfrom the insertion orientation to a rotated orientation in which theplanar inner surface of each of the blades is parallel to theintervertebral disc space; and (9) second operating the dual-motionretractor in a retraction mode to retract the pair of the opposing discsaway from one another to expand the blade-receiving aperture and toretract the opposing blade subassemblies away from one another and fromthe dilator.

Other embodiments are also disclosed.

Additional objects, advantages and novel features of the technology willbe set forth in part in the description which follows, and in part willbecome more apparent to those skilled in the art upon examination of thefollowing, or may be learned from practice of the technology.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention,including the preferred embodiment, are described with reference to thefollowing figures, wherein like reference numerals refer to like partsthroughout the various views unless otherwise specified. Illustrativeembodiments of the invention are illustrated in the drawings, in which:

FIGS. 1A-1B illustrate perspective and top partial views, respectively,of a patient's spine comprised of sequential vertebrae, each separatedby an intervertebral disc space, with an attached psoas muscle group;

FIGS. 2A-2B illustrate perspective views of a prior art retractionsystem including a series of increasing-diameter dilators and a circularlateral retractor, as inserted into the spine of FIGS. 1A-1B;

FIG. 3 illustrates a bottom-plan view of the prior art dilators andlateral retractor of FIGS. 2A-2B, as inserted into the psoas muscle andtrapping the muscle fibers;

FIGS. 4-6 illustrate respective perspective, top, and front views of oneembodiment of a rectangular dilator, as inserted at an insertionorientation through a patient's side body and through the psoas muscleover the intervertebral disc space of FIGS. 1A-1B;

FIG. 7 illustrates a perspective view of the rectangular dilator ofFIGS. 4-6;

FIG. 8 illustrates a perspective view of the rectangular dilator ofFIGS. 4-6, as inserted at the insertion orientation through the psoasmuscle over the intervertebral disc space and having a monitor cablecoupled with a conducting wire in electronic communication aneuromonitoring tip of the dilator;

FIGS. 9-10 illustrate perspective and side views, respectively, of oneembodiment of a dual-blade assembly passed over the inserted dilator ofFIGS. 4-8 in the insertion orientation;

FIGS. 11-14 illustrate left-perspective, right-perspective, top-plan,and left-bottom-perspective views, respectively, of one embodiment of ablade subassembly of the dual-blade assembly of FIGS. 9-10;

FIG. 15 illustrates a perspective view of the dual-blade assembly ofFIGS. 9-10 installed in the insertion orientation, without a lowercoupling device and disposed upon a surgical table in preparation forconnection with a lateral retraction gearbox;

FIG. 16 illustrates a perspective view of the dual-blade assembly ofFIGS. 9-10 including a lower coupling device attaching two of the bladesubassemblies of FIGS. 11-14, in preparation for connection with thelateral retraction gearbox of FIG. 15;

FIG. 17 illustrates a perspective view of the dual-blade assembly ofFIG. 16 in the insertion orientation, connected to the lateralretraction gearbox of FIGS. 15-16 via one embodiment of a rotationassembly;

FIG. 18 illustrates a perspective view of the connected dual-bladeassembly, lateral retraction gearbox, and rotation assembly of FIG. 17,with the dual-blade assembly rotated to a final rotated orientation viathe rotation assembly;

FIG. 19 illustrates a perspective view of one embodiment of a rotationgearbox and connecting rods of the rotation assembly of FIGS. 17-18;

FIG. 20 illustrates a perspective view of the connected dual-bladeassembly, lateral retraction gearbox, and rotation assembly of FIGS.17-18, with a handle of the rotation assembly removed and an embodimentof a pair of opposing passive lateral arms coupled between thedual-blade assembly and the lateral retraction gearbox;

FIG. 21 illustrates the assembly of FIG. 20, with a gearbox of therotation assembly removed;

FIG. 22 illustrates a perspective view of the assembly of FIG. 21, withone embodiment of a pair of opposing lateral drive arms coupled betweenthe dual-blade assembly and the lateral retraction gearbox;

FIG. 23 illustrates a perspective view of the assembly of FIG. 22, witha K-wire and a lower coupling device removed from the dual-bladeassembly to an exploded position;

FIG. 24 illustrates a perspective view of the assembly of FIG. 23, withthe dilator of FIGS. 4-8 removed to an exploded position;

FIG. 25 illustrates a perspective view of the assembly of FIG. 24, witha housing of the lateral actuation gearbox removed to reveal oneembodiment of a lateral retraction gear chain operating within thehousing;

FIGS. 26-27 illustrate top views of two adjacent blade subassemblies ofFIGS. 11-14 coupled with one embodiment of a lateral retraction assemblyand in a closed blade position;

FIGS. 28-30 illustrate top views of the two blade subassemblies coupledwith the lateral retraction assembly of FIGS. 26-27 in a retracted bladeposition;

FIG. 31 illustrates a perspective view of the two blade subassembliescoupled with the lateral retraction assembly in the retracted bladeposition of FIG. 30, as inserted through the patient's side body;

FIG. 32 illustrates a perspective view of one embodiment of a fullyassembled lateral retraction system;

FIG. 33 illustrates a perspective view of a surgical area illuminatedusing LEDs built into one embodiment of the lateral retraction system ofFIG. 32;

FIG. 34 illustrates a perspective view of an image area covered by avideo camera incorporated within one embodiment of the lateralretraction system of FIG. 32;

FIGS. 35A-35B provide a flowchart depicting an exemplary method ofcreating a surgical pathway to the patient's spine using the assembliesand systems of FIGS. 4-34

FIGS. 36A-36B illustrate perspective and cross-sectional views ofanother embodiment of a planar dilator featuring non-wired, continuous,and simultaneous neuromonitoring about 360-degrees of a circumference ofthe dilator;

FIGS. 37A-37F illustrate respective front, rear,partial-rear-perspective, partial-side-perspective, unassembledpartial-rear perspective, and assembled partial-rear perspective viewsof one embodiment of a blade and adjustable wings for incorporation intothe blade subassembly of FIGS. 11-18, featuring non-wired, continuous,and simultaneous neuromonitoring about 360-degrees of a circumference ofthe blade and the adjustable wings;

FIG. 38 illustrates a perspective view of one embodiment of adual-motion rotation and retraction system including a planar dilator, aretractable dual-blade assembly, and a dual-motion retractor;

FIGS. 39A-39B illustrate respective perspective and perspective-partialviews of an embodiment of the planar dilator of FIG. 38;

FIG. 40 illustrates a perspective view of the planar dilator of FIGS.39A-39B, as inserted at an insertion orientation through a patient'sside body and parallel to the fibers of psoas muscle over theintervertebral disc space;

FIGS. 41A-41H illustrate respective perspective, front, rear, left,right, top, top actuated, and exploded views of one embodiment of ablade subassembly of the dual-blade assembly of FIG. 38;

FIGS. 42A-42C illustrate perspective views of one embodiment of thedual-motion retractor of FIG. 38 positioned at an insertion orientationand a closed position, a rotated orientation and the closed position,and the rotated orientation and a retracted position, respectively;

FIG. 42D illustrates an exploded view of the dual-motion retractor ofFIGS. 42A-42C;

FIGS. 43A-43H illustrate the steps through which embodiments of thedual-motion rotation and retraction system of FIG. 38 are used to createa surgical pathway through the side of a patient's body, through thepsoas muscle, and to the intervertebral disc space; and

FIGS. 44A-44B provide a flowchart depicting an exemplary method of usingthe dual-motion rotation and retraction system of FIG. 38 to create thesurgical pathway through the side of the patient's body through thepsoas muscle to the patient's disc space, as shown in the steps of FIGS.43A-43H.

DETAILED DESCRIPTION

Embodiments are described more fully below in sufficient detail toenable those skilled in the art to practice the system and method.However, embodiments may be implemented in many different forms andshould not be construed as being limited to the embodiments set forthherein. The following detailed description is, therefore, not to betaken in a limiting sense.

This disclosure details a system and method of use for a lateralapproach to creating a minimally invasive surgical pathway through, oranterior to, a patient's side body and psoas muscle 102 to theintervertebral disc space 110 of the spine 100. Embodiments may includea lateral retractor system having a flat, narrow dilator having a bodythat tapers to a distal edge. The dilator inserted in a diagonalorientation that is parallel to the angled fibers of the psoas muscleand anchored into the disc space 110 via a K-wire. The dilator may beused in conjunction with a dual-blade lateral retractor that may beplaced in a corresponding diagonal orientation over the flat, narrowdilator before the entire system is rotated, at an angle of 0 degrees toless than 90 degrees, or approximately 45-50 degrees to the horizontal,or until the dilator and the lateral retractor are parallel with thedisc space 110, as shown and discussed in FIGS. 17-18 below. Once thesystem is rotated, the dilator may be removed and the dual blades of thelateral retractor may be laterally separated to push the muscle fibersaway, or apart, or both away and apart, and to complete the surgicalpathway in a manner that minimizes entrapment of, impingement upon,and/or damage to the patient's muscle fibers and nerve structures.Because the dilator is narrow or flat in shape, which allows the dilatorto be placed in its insertion orientation parallel to the muscle fibersand then rotated to its final rotated orientation parallel to the discspace, the system functions with a single element or component dilator,rather than requiring placement of a series of sequentially largercircular dilators, as discussed in the Background section above.

Both the dilator and the lateral retractor may incorporate real-time,360 degree neuromonitoring through stimulated horizontal wiringpositioned on the external sides/surfaces of each of the distal dilatortip and the distal ends of the blades of the lateral retractor, enablingreal-time and continuous neuromonitoring throughout the procedure fromfront to back and superior to inferior. Embodiments of the lateralretractor system may also incorporate built-in LED lighting for superiorsurgical visualization, as well as micro-video capabilities that enablethe system to be operated in the most ergonomic and efficient fashion.

Lateral Retractor System

Turning to exemplary embodiments, FIGS. 4-34 and 35A-35B generallyillustrate a method of using embodiments of a disclosed lateralretractor system 200 (FIG. 32) to employ a lateral surgical approach toclear a surgical pathway 114 to a patient's spinal disc space 110.Specifically and in one embodiment, FIGS. 4-34 detail a number of stepsin which exemplary devices are in use to create the surgical pathway 114through the side of a patient's body 108, through, or anterior to, thepsoas muscle 102, and to the intervertebral disc space 110, while FIGS.35A-35B provide a flowchart depicting an exemplary method 500 ofcreating the surgical pathway 114 through the side of the patient's body108 through, or anterior to, the psoas muscle 102 to the disc space 110.

Employing fluoroscopy imaging technology, a dilator 202 may be placedover/adjacent to the intervertebral disc space 110 (FIG. 35A, 501).Specifically, and referring to FIGS. 4-7, the dilator 202 may enterthrough an incision 118 in the patient's side body 108 (FIG. 35A, 502),cut through any intervening fascia (FIG. 35A, 504), and then traversethe psoas muscle 102 in a direction, or at an insertion orientation 239,that is “along,” or parallel to the muscle fibers of the psoas muscle102, and diagonal to, or angled at 0 degrees to less than 90 degrees to,the patient's spine 100 (FIG. 35A, 506). The psoas muscle 102 may beaccessed via the side of the patient's body 108 such that the dilator202 protrudes from a lateral surface 116 of the patient's body 108 wheninserted to full depth at the spinal column 100.

FIG. 7 illustrates a perspective view of one embodiment of the dilator202. In this embodiment, the dilator 202 may feature a flat, narrow body204 having opposing flat surfaces 209 that extend between a proximal end206 for positioning at the lateral surface 116 of the patient's sidebody 108 (FIG. 4) and a distal end 208 for positioning adjacent thepatient's spine 100. The longitudinal sides of the narrow body 204 ofthe dilator 202 may taper to opposing longitudinal edges 212, and thedistal end 208 of the dilator 202 may taper to a distal edge 210 capableof cutting through the patient's fascia and traversing the fibers of thepsoas muscle 102 in the parallel manner described above. As a result,the dilator 202 separates, rather than crushes, the fibers of the psoasmuscle 102 as it traverses through the psoas muscle 102 to the spine100, as shown in FIGS. 4-6 and 8.

The dilator 202 may also include a K-wire access aperture 216 thatextends longitudinally through the body 204 of the dilator 202. Inaddition, conducting wires 218 may extend longitudinally through eachside of the body 204 of the dilator 202. At the distal end 208 of thedilator 202, the conducting wires 218 may be in electronic communicationwith a set of horizontal neurosensing wires 220 that are integrated orbuilt into each side of the tapered distal end 208 of the dilator 202.At the proximal end 206 of the dilator, the conducting wires 218 may bein electronic communication with a monitoring cable 224, shown in FIG.8, which may be configured to conduct an electronic stimulus through theconducting wires 218 to the horizontal neurosensing wires 220, formingan active neuromonitoring tip 222 about an entirety of the distal end208 of the dilator 202. Alternatively, the conducting wires 218 may bein wireless electronic communication to neuromonitoring tip 222.

Impingement of the active monitoring tip 222 upon, or alternatively,encroachment of the active monitoring tip 222 in close proximity tonerve structures located along the patient's spine 100 may stimulatethose nerve structures that are nearby or adjacent to the activemonitoring tip 222. The voltage of the applied electronic stimulus maybe adjusted as necessary and/or required to stimulate nerve structureswithin a defined distance of the active monitoring tip 222. This appliedstimulus causes the nerve structure(s) to fire and generate a responsivesignal, which may in turn be conducted from the active monitoring tip222, through the conducting wires 218, and to the monitoring cable(s)224 in electronic communication with one or both of the conducting wires218 at the proximal end 206 of the dilator 202, as shown in FIG. 8,thereby translating the neurosensing stimulation of the activemonitoring tip 222 by the nearby nerve structure(s) to externalmonitoring equipment (not shown) via the monitoring cable 224 anddetermining, in real time and with 360 degrees of monitoring range orfield of view about the distal end 208 of the dilator 202, a possibilityof nerve or plexus injury as the dilator 202 is inserted (FIG. 35A,508).

Embodiments of the dilator 202 and its components may be formed of anyappropriate conductive or nonconductive, autoclavable or otherwisesterilizable metal or plastic. In addition, the body 204 of the dilator202 may have any appropriate length to accommodate the patient's size,shape, and/or physiology. In one embodiment, the dilator 202 may beprovided in a variety of lengths, allowing the surgeon to select inreal-time the appropriate length for the patient.

Once the distal edge 210 of the dilator 202 is positioned at the spine100 in the insertion orientation 239 that is parallel to the fibers ofthe psoas muscle 102 and spanning the disc space 110 diagonally at anangle of 0 degrees to less than 90 degrees, and in some instances at anangle of 0 degrees to less than 90 degrees, or in some instances at anapproximate 45-degree angle, a K-wire 214 may be passed longitudinallythrough the access aperture 216 of the dilator 202 and into the spine100 at the disc space 110 (FIG. 35A, 510), both stabilizing and securingthe position of the dilator 202, as shown in FIGS. 6 and 8. Because ofthe active monitoring tip 222, the full range of monitoring—front toback and superior to inferior—may continue after the dilator 202 isfixed via the k-wire 214. Unlike previous devices featuring pinpointelectrodes that require manual rotation to perform 360 degrees ofmonitoring, the active monitoring tip 222 remains active and provides ageometry capable of monitoring in 360 degrees during every stage of itsinsertion and use during a procedure.

Referring to FIGS. 9-10, after securing the K-wire 214 (FIG. 35A, 510)into the disc space 110 of the spine 100 such that the dilator 202 isstabilized, secured, and providing continuous neuromonitoring, adual-blade assembly 230 of a dual-blade lateral retractor system 200(FIG. 32) may be passed over or introduced at the insertion orientation239 alongside the dilator 202 such that each blade 244 of the dual-bladeassembly 230 opposes and contacts one of the opposing flat surfaces 209of the dilator 202 to further minimize damage to nerve structures andmuscle fibers (FIG. 35A, 512).

As shown in FIGS. 9-10, the dual-blade assembly 230 may include twoopposing and identical blade subassemblies 240 coupled to one anothervia a lower coupling device 242 configured to snap or press fit intoreceiving structures formed within each of the blade subassemblies 240.The lower coupling device 242 may include a platform 241 having aplurality of protrusions extending from a bottom of the platform 241that are sized to be received by each of the blade subassemblies 240.The protrusions may include two opposing rectangular protrusions 243 andfour opposing circular protrusions 245, each for insertion into acorresponding one of the blade subassemblies 240. The lower couplingdevice 242 may also include two circular receivers 247 formed within atop of the platform 241 and configured to receive components ofadditional functional assemblies that stack above the blade assembly230, as detailed further below.

FIGS. 11-13 illustrate front-perspective, rear-perspective, and top-planviews of one exemplary embodiment of the blade subassembly 240,respectively. In this embodiment, the blade subassembly 240 may includea blade 244 having a planar inner surface 235 that faces the opposingblade 244 of the dual-blade assembly 230 (FIGS. 9-10), an outer surface237, a proximal blade portion 246, a detachable distal blade portion248, and opposing longitudinal edges 250 that extend between a proximalend 260 of the proximal blade portion 246 and a distal end 255 of thedistal blade portion 248. Opposing adjustable wings 252 may be hingedlycoupled with each of the opposing longitudinal edges 250, as detailedfurther below.

Turning to the blade 244, the detachable distal portion 248 may be adisposable, single-use insert of any appropriate length to accommodatethe patient's size or physiology. In one embodiment, a plurality ofdetachable distal portions 248 may be provided in a peel pack (notshown), where each of the distal portions 248 contained within the peelpack feature a different length to accommodate a variety patient sizesand/or physiologies, which results in a variety of distances to traversebetween the lateral surface 118 of the patient's body 108 and the spine100. During use, the surgeon may select the detachable distal bladeportion 248 with the appropriate length before attaching the selectdistal blade portion 248 to the reusable and sterilizable proximalportion 246 of the blade 244. The detachable distal portion 248 mayattach to the reusable proximal portion 246 in any appropriate mannerincluding, for example, a snap-fit of mating components or, as shown inFIG. 12, via an attachment screw 254 or another appropriate threadedfastener.

In one embodiment, the distal end 255 of the distal portion 248 of theblade 244 may form an active monitoring tip 256 similar to the activemonitoring tip 222 of the dilator 202. In this regard, horizontalneurosensing wires 258 may be incorporated or built into the outersurface 237 of the blade 244 at the active monitoring tip 256. Thehorizontal neurosensing wires 258 may detect any impingement orencroachment upon nerve or plexus, and the resulting stimulus may beconducted through conducting wires embedded longitudinally in the blade,and through a monitoring cable for reporting to external equipment. Viathe active monitoring tip 256 of each of the distal blade portions 248of the blades 244, continuous real-time neuromonitoring may be performedto prevent nerve or plexus injury when the blade assembly 230 isinserted over the dilator 202 (FIG. 35A, 512, 514), as well as when theblade assembly 230 is rotated (FIG. 35A, 516) and/or laterally separatedor retracted (FIG. 35A, 524), as discussed below. Unlike existingsystems, neuromonitoring over a full 360-degree monitoring range maycontinue throughout the procedure.

The sterilizable and reusable proximal blade portion 246 may include anumber of unique features that aid the surgeon. In one embodiment, theproximal end 260 of the proximal blade portion 246 may form a generallyrectangular or elliptical receiver 262 (or other similar geometricalconfiguration) configured to receive one of the rectangular orelliptical protrusions 243 of the lower coupling device 242 (FIGS.9-10), which is adapted to temporarily couple the dual, opposing bladesubassemblies 240 to one another during insertion and assist in rotatingthe blade subassemblies 240 from the insertion orientation 239 to afinal, rotated orientation, as discussed below in relation to FIGS.17-18.

In addition, and referring to FIGS. 11-14, one or more light emittingdiode (LED) lights 264 may be built into the proximal blade portion 246.As shown in FIGS. 11 and 14 and in this embodiment, three LED lights 264may be positioned adjacent to the inner surface 235 of a distal end 261of the proximal blade portion 246, such that the LED lights 264illuminate a surgical area 266, as shown in FIG. 11. In one embodimentshown in FIG. 14, the LED lights 264 may be mounted to a printed circuitboard (PCB) 265 housed within a PCB chamber 267 formed within theproximal blade portion 246 of the blade 244. The PCB 265 may incorporatecontrol or interface circuitry that is, in turn, electrically coupledwith a power source and a switch 272. In this embodiment, the powersource may be one or more lithium ion batteries 268 housed within abattery housing 270 that is affixed in any appropriate manner to theouter surface 237 of the blade 244, as shown in FIGS. 11-13. The switch272 may be electrically coupled between the batteries 268 and the PCB265/LED lights 264, such that the switch 272 is configurable to controlthe lights 264 as necessary and/or desired by the surgeon. For example,the switch may be operated to illuminate a single one of the LED lights264, a pair of the lights 264, or all of the LED lights 264 depending onthe applicable light requirements and/or requisite run times.

Built-in lighting on the inner surfaces 235 of the blades 244 providesmore accurate visualization for the surgeon due to the proximity of thelight emitting source to the surgical field 266. The built-in lightingalso eliminates the need for an external extension cord for lightingpurposes, and prevents light projected from a separately attached lightsource, which is often attached to a proximal end of the apparatus, fromreflecting off the blades and into the surgeon's eyes during operation.

The blade 244 may also include video capability to provide ergonomicoperation for the surgeon. Specifically, and in one embodiment shown inFIG. 14, an interior of the proximal blade portion 246 may form a camerareceiver channel 274 into which a video camera 276 (e.g., a commerciallyavailable micro-video camera) may be fed or positioned to provide aclear view of the surgical field 266. Images captured by the videocamera 276 may be transmitted to one or more external monitors (e.g.,flat screen television monitors) (not shown) via a video output 278electronically coupled between the video camera 276 and the monitor(s).In one embodiment, the video camera 276/video output 278 may employwireless technology such as, for example, a Bluetooth, Zigbee, Wi-Fi oranother appropriate transmitter or transceiver to communicate with theexternal monitoring devices. This video capability enables the surgeonto view his or her work within the surgical field 266 inside thedual-blade assembly 230 on the external monitors, and relieves thesurgeon of the need to look straight down the assembly throughout thecourse of the procedure being performed.

As discussed above, each of the longitudinal edges 250 of the blade 244may hingedly couple with an adjustable wing 252, as shown in FIGS.11-14. As detailed below in relation to FIGS. 25-31, the adjustablewings 252 may be rotated or adjusted through 90 degrees relative to theinner surface 235 of the blade 244—from an open position 280 that isparallel with the blade 244 (FIGS. 25-27) to a closed position 282 thatis perpendicular to the blade 244 (FIG. 30), and any positiontherebetween (FIGS. 28-29). This adjustment from the open position 280to the closed position 282 essentially sections off the musclesurrounding the dual-blade assembly 230 as the blades 244 are separatedor retracted away from one another, thereby preventing any “creep” ofthe muscle between the blades during retraction and enabling thedual-blade assembly 230 to accomplish what has previously requiredadditional blades (e.g., multiple blades beyond two, a circular orradial blade configuration) to complete.

FIGS. 12-13 illustrate a perspective view of the blade subassembly 240and a top view of the blade subassembly 240 with the battery housing 270removed, respectively. Specifically, FIGS. 12-13 detail an exemplaryactuation assembly 290 for the adjustable wings 252 on each blade 244.In this embodiment, the actuation assembly 290 may include a centralmiter gear 292 positioned horizontally such that a center axis 294defined by the central miter gear 292 runs parallel to the blade 244. Atop of the central miter gear 292 may form a hexagonal socket 296configured to receive an actuating hex key (not shown), which may takethe form of a removeable manual handle such as handles 310 and 316,discussed below in relation to the rotation and lateral retractionassemblies.

The central miter gear 292 may be enmeshed between two opposing verticalmiter gears 298, each defining a center axis 300 that is perpendicularto and that intersects the center axis 294 of the central miter gear292. Each of the vertical miter gears 298 may be affixed to a worm screw302 that is, in turn, enmeshed with a corresponding worm wheel 304affixed to a proximal end of the associated adjustable wing 252. Tooperate, the hex key/handle may be rotated within the hexagonal socket296 to rotate the central miter gear 292, which, in turn rotates thevertical miter gears 298, the attached worms screws 302, and thecorresponding worm wheels 304 affixed each adjustable wing 252 to movethe wings 252 through 90 degrees in the direction of arrow C relative tothe inner surface 235 of the blade 244, as shown in FIGS. 25-31.

Like the lower blade portion 248, the adjustable wings 252 may besingle-use components that vary in length based upon an overall lengthof the blade 244 required to accommodate the patient's size and/orshape. Moreover, each of the adjustable wings 252 may form an activemonitoring tip 283 (FIG. 12) on its outer surface similar to the activemonitoring tips 222 and 256 of the dilator 202 and the blade 244,respectively.

Returning to the method and in relation to FIGS. 15-19, after thedual-blade assembly 230 is passed over the dilator 202 (which may beelliptical, rectangular, or any other similar geometrical configuration)in a direction along the fibers (either anterior or trans) of the psoasmuscle 102 (FIG. 35A, 512), the dual-blade assembly 230 may be rotatedin some instances approximately 0 degrees to less than 90 degrees, or inother instances approximately 45-50 degrees in the direction of arrow Aabout the K-wire 214, from its initial insertion orientation 239parallel to the fibers (either anterior or trans) of the psoas muscle102, shown in FIGS. 15-17, to a final rotated orientation 306 parallelto the disc space 110, in which the blades 244 of the dual-bladeassembly 230 are positioned transverse (or anterior) to the fibers ofthe psoas muscle 102 and begin to separate the fibers of the psoasmuscle 102, as shown in FIG. 18 (FIG. 35B, 516).

To rotate the dual-blade assembly 230 from the insertion orientation 239to the rotated orientation 306 (FIG. 35B, 516), additional assembliesmay be operably coupled with the dual-blade assembly 230, as shown inFIGS. 15-19. Initially, a lateral actuation gearbox 308 and an actuatinghandle 310 may be securely attached to a fixed reference point such as asurgical table 233 via a standard tooth jaw and universal jointmechanism (not shown) (FIG. 35B, 518), as shown in FIG. 15. Then arotation assembly 312 may be coupled between the blade assembly 230 andthe lateral actuation gearbox 308 (FIG. 35B, 520).

In further detail and in one embodiment shown in FIGS. 17-19, therotation assembly 312 may include a rotation gearbox 314, an actuatinghandle 316, and a pair of connecting rods 318 coupled between therotation gearbox 314 and the lateral actuation gearbox 308, each havinga first end 320 affixed to a housing 324 of the rotational gearbox 314and a second end 322 affixed to a housing 342 of the lateral actuationgearbox 308. The first and second ends 320, 322 of the connecting rods318 may be affixed to the rotational gearbox housing 324 and the lateralactuation gearbox housing 342, respectively, in any appropriate mannerincluding, for example, via threaded fasteners.

FIG. 19 illustrates a perspective view of one embodiment of the rotationgearbox 314 and the connecting rods 318, with the housing 324 of therotation gearbox 314 in which the housing 324 is shown in wireframe toreveal the details of the gearbox 314. In this embodiment, the rotationgearbox 314 may contain first, second, and third rotational gears 326,328, 330, respectively, that are rotationally mounted relative to oneanother within the housing 324. The first rotational gear 326 mayinclude a hexagonal or other appropriately configured socket 332 adaptedto receive a distal end of the handle 316, which, in this embodiment,may be configured as a hex key. The third rotational gear 330 may beaffixed to an upper coupling device 334 having a top surface 336 adaptedto attach to the third rotational gear 330 and a bottom surface 338having two circular protrusions 340 extending therefrom. Each of thecircular protrusions 340 may, when the rotation gearbox 314 is assembledto the blade assembly 230 as shown in FIGS. 17-18, extend into thecircular receivers 247 of the lower coupling device 242 of the bladeassembly 230, shown in FIG. 16 and detailed above in relation to FIGS.9-10.

Once the rotation assembly 312 is coupled between the blade assembly 230and the lateral actuation gearbox 308 (FIG. 35B, 520), as shown in FIG.17, the handle may be manually actuated (FIG. 35B, 522) to turn thefirst rotational gear 326, which, in turn, rotates the enmeshed secondrotational gear 328 and then the enmeshed third rotational gear 330.Because the lateral actuation gearbox 308, the connecting rods 318, andthe rotation gearbox 314 are fixed relative to the operating table (notshown), rotation of the third rotational gear 330 causes the uppercoupling device 334 to turn the attached lower coupling device 242 aboutthe K-wire 214, which causes the two attached blade subassemblies 240 torotate in the direction of arrow A (FIGS. 15-16) from the initialinsertion orientation 239 of FIG. 17 to the final rotated orientation306 of FIG. 18.

After the dual-blade assembly 230 has been rotated into the finalrotated orientation 306 (FIG. 35B, 516), the system may be reconfiguredfor separation, or lateral retraction, of the two opposing bladesubassemblies 240 via the steps illustrated in FIGS. 20-25 (FIG. 35B,524). First, and as shown in FIG. 20, a pair of opposing passive lateralarms 344 may be attached between the lateral actuation gearbox 308 andthe battery housings 270 of the blade subassemblies 240 (FIG. 35B, 526).Each of the passive lateral arms 344 may have a first end 346 that isrotationally coupled with one of the battery housings 270 and a secondend 348 that is rotationally coupled with the housing 342 of the lateralactuation gearbox 308, such that the passive lateral arms 344 mayprovide stabilization to the blade assembly 230 as the rotation gearbox314 is removed, as shown in FIG. 21, as well as passively accommodatethe lateral separation of the blade subassemblies 240, as discussedfurther below in relation to FIGS. 26-31. The rotational couplingsbetween the passive lateral arms 344, the battery housings 270, and thelateral actuation gearbox 308 may take any appropriate shape,configuration, or type. In this embodiment, the first and the secondends 346, 348 of each of the passive lateral arms 344 may form areceiver 350 configured to receive a corresponding protrusion 352extending from the battery housing 270 and from the lateral actuationgearbox 308 via a friction fit.

Once the passive lateral arms 344 are attached (FIG. 35B, 526), therotation assembly 312, including the rotation gearbox 314, the manualhandle 316, and the connecting rods 318, may be removed as shown inFIGS. 20-21 by disengaging the upper and the lower coupling devices 334and 242, all the while relying on the passive lateral arms 344 forstabilization of the blade assembly 230 during removal (FIG. 35B, 528).Then a pair of opposing lateral drive arms 354 may be coupled betweenthe lateral actuation gearbox 308 and the battery housings 270 of theblade subassemblies 240 (FIG. 35B, 530), as shown in FIG. 22. Each ofthe lateral drive arms 354 may have a first end 356 that is rotationallycoupled to one of the battery housings 270 of the blade subassemblies240 and a second end 358 that is rotationally coupled to the housing 342of the lateral actuation gearbox 308. These rotational couplings maytake any appropriate form, though in one embodiment, they may mimic thestructure of the rotational couplings of the passive lateral arms 344 inthat each of the first and the second ends 356, 358 may form a receiver360 configured to receive a corresponding protrusion 362 extending fromthe battery housing 270 and from the lateral actuation gearbox housing342, respectively, via a friction fit.

After the lateral drive arms 354 are attached, the K-wire 214 and thelower coupling device 242 may be removed, as shown in FIG. 23 (FIG. 35B,532), followed by the dilator 202, as shown in FIG. 24 (FIG. 35B, 534).

After removal of the K-wire 214, the lower coupling device 242, and thedilator 202, a lateral retraction assembly 370, which, in thisembodiment, may include the handle 310, the lateral actuation gearbox308, the opposing passive lateral arms 344, and the opposing lateraldrive arms 354, may be employed to separate or laterally retract theblade subassemblies 240 from a closed position 390, shown in FIGS.25-27, to a retracted position 392, shown in FIGS. 28-31 (FIG. 35B, 524,536).

In further detail, FIG. 25 illustrates a perspective view of the lateralretraction assembly 370 having an open housing 342 of the lateralactuation gearbox 308 to detail one embodiment of the mechanics of thegearbox 308. In this embodiment, the handle 310 may incorporate a wormgear 372 at its distal end. The worm gear 372 may be positioned betweenand enmeshed with two opposing lateral gears 374, one bordering eitherside of the worm gear 372. Each of the lateral gears 374 may include apivot point 375 about which the remaining components of the gear 374rotate, a teeth portion 376 that engages with the worm gear 374, and adrive portion 378 containing a protrusion 362 configured to frictionallyfit within the receiver 360 of the second end 358 of one of the lateraldrive arms 354.

The teeth portion 376 of each of the lateral gears 374 may have avariable radius that extends between the pivot point 375 and the teethportion 376. The variable radius may increase from a first radius, r₁,located at a first end 380 of the teeth portion 376 to a larger secondradius, r₂, located at a second end 382 of the teeth portion 376.

In actuating the lateral retraction assembly 370 (FIG. 35B, 536),rotation of the worm gear 372 via the handle 342 causes the enmeshedteeth portions 376 of the opposing lateral gears 374 to travel from thefirst ends 380 engaged with the worm gear 372 at the smaller radius, r₁,to the second ends 382 engaged with the worm gear 372 at the largerradius, r₂. This travel causes the lateral gears 374 to pivot about thepivot points 375, such that the drive portions 378 of the gears swingoutward in the direction of arrow B as the radius of each lateral gear374 increases from r₁ to r₂. This outward trajectory, in turn, drivesthe lateral drive arms 354, and thus the connected blade subassemblies240, in the outward direction of arrow B, from the closed position 390of FIGS. 25-27 to the retracted position 392 of FIGS. 28-31.

Before, after, or at increments during the process of actuating thelateral retraction assembly 370 (FIG. 35B, 536), and as discussed abovein relation to FIGS. 11-13, the wing actuation assembly 290 of eachblade subassembly 240 may be employed to adjust the adjustable wings 252from the open position 280 parallel with the blades 244, shown in FIGS.25-27, the closed position 282 perpendicular to the blades 244, shown inFIG. 30, and any position therebetween, such as the angled position(e.g., 27 degrees relative the blade 244), shown in FIGS. 28-29 and 31(FIG. 35B, 538). In this regard, the two opposing blades 244 aresufficient for lateral retraction, without the need for additionalblades as required by existing retractor systems, as the adjustablewings 252 prevent creep of the muscle between the blades 244 and intothe surgical pathway 114 during retraction. Throughout the steps ofrotating the dual-blade assembly 230 from the insertion orientation 239to the rotated orientation 306 (FIG. 35B, 516), laterally retracting theblade subassemblies 240 from the closed position 390 to the retractedposition 392 (FIG. 35B, 524), and adjusting the adjustable wings 252between the open position 280 and the closed position 282 (FIG. 35B,538), the active monitoring tips 256 and 283 of the blades 244 and thewings 252, respectively, may be used to provide real-timeneuromonitoring to prevent impingement and/or encroachment upon adjacentnerve structures (FIG. 35B, 542).

FIG. 32 illustrates a perspective view of a fully assembled lateralretractor system 200, including all of the components, assemblies, andsubassemblies discussed above. In addition and in this embodiment, thehousing 342 of the lateral actuation gearbox 308 may incorporate a level384 to assist in positioning components of the system 200 when carryingout the disclosed method 500 of creating a surgical pathway 114 usingembodiments the lateral retractor system 200, as provided in FIG. 35.The level 384 may be calibrated to level the system with respect to thefloor, the surgical table 233, or any appropriate reference plane.Relying on the level 384 for partial positioning reduces the amount ofreal-time x-ray technology (e.g., fluoroscopy) required to locate thesystem 200 during operation, resulting in less radiation exposure to thepatient, the surgeon, and everyone else in the operating theater. In oneembodiment, the level 384 may be a bubble or spirit level, or the levelmay be a gyroscope.

Once the lateral retraction assembly 370 has been employed to retractthe blade subassemblies 240 to form the surgical pathway 114, thesurgeon may access the spine 100 (FIG. 35B, 540) via the resultingsurgical pathway 114, leveraging the LED lights 254 illuminating thesurgical area 266 as desired, as shown in FIG. 33, and observing theimages transmitted from the surgical area 266 via the video output 278from the video cameras 276, as shown in FIG. 34.

Each of the components that form embodiments of lateral retractor system200 discussed above may be formed of any appropriate conductive ornonconductive, autoclavable or otherwise sterilizable metal or plasticusing any appropriate manufacturing method. As discussed, somecomponents may be disposable to improve efficiency and customizabilityand reduce the possibility of disease transmission, while others may bereusable and sterilizable.

Embodiments of the lateral retractor system 200 provide three separatekinds of movement—rotation of the single-component dilator 202 and thedual-blade assembly 230 from the insertion orientation 239 to the finalrotated orientation 306, rotation of the adjustable wings 252 from theopen position 280 to the closed position 282, and retraction of theblade subassemblies 240 from the closed position 390 to the retractedposition 392—that allow for a more sophisticated initial placement ofthe single-component dilator 202 and the dual-blade assembly 230 in amanner parallel to the psoas muscle 102 and, therefore, less damaging tothe muscle and nerve structures adjacent to the patient's spine. Ratherthan crushing or trapping sensitive body tissues beneath the dilatorand/or the blade assembly, the disclosed lateral retractor systemenables embodiments of the dilator 102 and the dual-blade assembly 230to bypass those tissues and instead “separate” them to create thesurgical pathway 114, as desired, with the use of an elegant design thatfeatures only two blades. In addition, rotation of the flat, narrowdilator 202 allows the dilator 202 to separate the psoas muscle tissueswithout the need for a more complicated series of progressively largercircular dilators, as required in the prior art.

Further, built-in lighting and video capabilities provide the surgeonwith streamlined and flexible lighting of the surgical area and theability to view his or her actions without hunching over the patientand/or the surgical apparatus. Detachable and disposable distal bladeportions and adjustable wings allow the system to accommodate anypatient physiology and can be selected in the operating theater asdeemed necessary by the surgeon. In sum, the unique lateral retractorsystem allows for a lateral approach to the spine to be made in a moresafe and efficient manner for the patient and for the surgeon.

In addition, continuous, real-time neuromonitoring via the activeneuromonitoring tips 222, 256, and 283 located at the distal ends of thedilator 102, the blades 244, and the adjustable wings 252, respectively,further assists in reducing damage to the patient's nerves and plexus inthat the system may continuously monitor, and avoid, impingement orencroachment upon nerve structures within a 360-degree monitoring rangeabout the circumference of the system 200. This continuousneuromonitoring occurs throughout the process of forming the surgicalpathway 114 and any subsequent surgical procedure.

In one embodiment shown in FIGS. 36A-36B, a dilator 202 a may besubstituted for the dilator 202, discussed above, to provideneuromonitoring capabilities free of internal wires. In this embodiment,the dilator 202 a may be formed of a conductive material such as, forexample, aluminum and may leverage the internal conductivity of thedilator's rectangular body 204 a to form a conductive electrical pathway205 between one or more conductive input surfaces 207 formed at aproximal end 206 a of the rectangular body 204 a and a conductive activemonitoring tip 222 a disposed at a distal end 208 a of the rectangularbody 204 a.

In this embodiment, the electrical pathway 205 may be configured viaselective shielding applied to portions of the dilator 202 a. Forinstance, dilator surfaces intended to be nonconductive, insulatedsurfaces may be coated with an insulative or nonconductive layer. In oneembodiment, a portion of an outer surface 211 of the aluminum body 204 amay be coated with an anodized layer 213, which may be nonconductive andalso provide a hardened surface that resists scratching and other damageto the dilator 202 a. In one embodiment, a non-stick material such asTeflon may be added to the anodization to render the anodized layer 213“slippery” such that the dilator 202 a more easily glides relative toother system components and/or bodily tissues during the insertion andremoval processes.

In applying the anodized layer 213, portions of the outer surface 211that are desired to be free of anodization, and thus conductive, may bemasked during the anodizing process. In this embodiment, the conductiveinput surfaces 207 and the active monitoring tip 222 a may be maskedsuch that those surfaces remain conductive in their entireties. Thus,when an electrical signal is applied, through the monitoring cable 224(FIG. 8) or otherwise, to the dilator 202 a at the conductive inputsurfaces 207 at the proximal end 206 a of the dilator 202 a, the signaltravels via the conductive electrical pathway(s) 205 to the activemonitoring tip 222 a, which spans 360 degrees of the distal end 208 a ofthe dilator 202 a.

Impingement or encroachment of the active monitoring tip 222 a upon oneor more nerve structures causes the nerve structures to fire andgenerate a responsive signal, which is conducted back through theelectrical pathway(s) 205 to the monitoring cable(s) 224 incommunication with the electrical pathway(s) 205 at the conductive inputsurfaces 207, thereby translating the neurosensing stimulation of theactive monitoring tip 222 a to external monitoring equipment (not shown)via the monitoring cable 224 and determining, in real time, with 360degrees of monitoring range, and with an internal-wire-free mechanismthat is more simply and cost-effectively manufactured, a possibility ofnerve or plexus injury as the dilator 202 a is inserted (FIG. 35A, 508).

In a manner similar to the dilator, the blades and the adjustable wingsmay also be configured for continuous, real-time, 360-degreeneuromonitoring that does not require a wired electrical pathway withintheir components. FIGS. 37A-37F illustrate front, rear, and numerouspartial views of an exemplary embodiment of a blade 244 a, hingedlybordered by two opposing adjustable wings 252 a. In operation and in oneembodiment, the blade 244 a and the wings 252 a may be electivelysubstituted for the blade 244 and the wings 252 described above. In thisembodiment, the blade 244 a and the wings 252 a are similar to the blade244 and the wings 252, discussed above, in both structure and function,and additionally feature no-wire neuromonitoring capabilities similar tothe dilator 202 a, discussed above in relation to FIGS. 36A-36B.

In further detail and as shown in FIGS. 37A-37B, the blade 244 a mayhave a proximal blade portion 246 a, a detachable, disposable distalblade portion 248 a, and opposing longitudinal edges 250 a that extendbetween a proximal end 260 a of the proximal blade portion 246 a and adistal end 255 a of the distal blade portion 248 a. The opposingadjustable wings 252 a may be hingedly coupled with each of the opposinglongitudinal edges 250 a via a plurality of hinge pins 249, as shown inFIGS. 37A-37B.

In this embodiment, all components forming the blade 244 a and theadjustable wings 252 a, including the proximal blade portion 246 a, theremoveable and disposable distal blade portion 248 a, the wings 252 a,and the hinge pins 249, may be formed of a conductive material such as,for example, aluminum and may be strategically coated with anonconductive, insulated layer such as an anodized layer 271 so as toform an internal conductive electrical pathway 253 through the multiplecomponents. In this regard, the proximal portion 246 a of the blade 244a may include at least one conductive electrical connection point,conductive input surface, or “jack” 251, shown in FIGS. 37C-37D, and thedistal portion 248 a of the blade 244 a and the opposing adjustablewings 252 a may each terminate distally in respective active monitoringtips 256 a, 283 a similar to the active monitoring tip 222 a of thedilator 202 a. As shown in FIGS. 37E-37F, select surfaces of theproximal blade portion 246 a and the distal blade portion 248 a may bemasked so as to form adjacent and contacting electrically conductivesurfaces 257, 259 when the proximal and distal blade portions 246 a, 246b are assembled together.

In operation, the electrical connection point 251 may act as an inputpoint where electrical conduction initiates, via the monitoring cable224 or another appropriate source, such that an applied electricalsignal conducts from the electrical connection point 251, through theproximal blade portion 246 a, to and through the wings 252 a via thepins 249, to and through the distal blade portion 248 a via theconductive surfaces 257, 259, and through the active monitoring tips 256a, 283 a along the conductive electrical pathway 253 shown in FIG. 37B.This stimulus of the active monitoring tips 256 a, 283 a causes nearbynerve structures to fire and generate a responsive electrical signal,which may in turn be conducted back from the active monitoring tips 256a, 283 a to the electrical connection point 251 and to the monitoringcable 224 in electronic communication with external monitoringequipment, thereby sensing the stimulation of the active monitoring tips256 a, 283 a caused by proximity to nearby nerve structure(s) in realtime and with 360 degrees of monitoring range or field of view about anentirety of the distal ends of the blade 244 a and the wings 252 a.Thus, via the active monitoring tips 256 a, 283 a of each of the distalblade portions 248 a of the blades 244 a, continuous real-timeneuromonitoring may be performed to prevent nerve or plexus injury whenthe blade assembly 230 is inserted over the dilator 202 a (FIG. 35A,512, 514), as well as when the blade assembly 230 is rotated (FIG. 35A,516) and/or laterally separated or retracted (FIG. 35A, 524), asdiscussed above. Unlike existing systems, neuromonitoring over a full360-degree monitoring range may continue throughout the procedure.

Due to the multi-component nature of the wings as assembled to theblade, the internal conductive electrical pathway 253 avoids thecomplexity of a design which routes a wired pathway to the activemonitoring tips 256 a, 283 a, allowing for a more streamlined instrumentwith fewer components that is more efficient and less expensive tomanufacture.

Dual Motion Rotation and Retraction System

Embodiments of a dual-motion rotation and retraction system 1200, shownin FIG. 38, may provide the three separate types of movement discussedabove—rotation of a single-component dilator 1202 and a dual-bladeassembly 1230 from the insertion orientation 239 to the final rotatedorientation 306, retraction of two opposing blade subassemblies 1240from the closed position 390 to the retracted position 392, and rotationof sets adjustable blade wings 1152 from an open position 1280 to aclosed position 1282—using a streamlined combination of a dilator 1202,a dual-blade assembly 1230 including two opposing and identical bladesubassemblies 1240, and a dual-motion retractor 1300.

Turning to exemplary embodiments, FIGS. 39A-39B illustrate respectiveperspective and partial perspective views of one embodiment of thesingle-component dilator 1202. The dilator 1202 includes features andfunctionalities similar to the dilator 202 a, discussed above inrelation to FIGS. 36A-36B, and similarly provides neuromonitoringcapabilities free of internal wires. In this embodiment, and like thedilator 202 a, the dilator 1202 may be formed of a conductive materialsuch as, for example, aluminum and may leverage the internalconductivity of its rectangular body 1204 to form a conductiveelectrical pathway between one or more conductive input surfaces 1207formed across a proximal end 1206 of the rectangular body 1204 and aconductive active monitoring tip 1222 disposed at a distal end 1208 ofthe rectangular body 1204. In addition to a nonconductive coating (e.g.,an anodized layer) 1213, the dilator 1202 may include an anti-glarecoating to prevent glare or reflection into the blade cameras.

In this embodiment, the wireless active neuromonitoring operates in themanner described above in relation to dilator 202 a of FIGS. 36A-36B.However, and as shown in FIGS. 39A-39B, the proximal end 1206 of thedilator 1202 may comprise opposing chamfered surfaces 1210, while theactive neuromonitoring tip 1222 at the distal end 1208 may form abullnosed curve at a shallow angle relative to the outer surfaces 1211of the rectangular body 1204. Both of these geometries allow the dilator1202 to better accommodate the opposing inner faces of the blades 1244,shown and discussed below in relation to FIGS. 41A-41H.

FIG. 40 illustrates a perspective view of the dilator 1202 with thedistal end 1208 positioned adjacent the patient's spine 100 in theinsertion orientation 239 parallel to the fibers of the psoas muscle 102and spanning the disc space 110 diagonally at an approximate 45-degreeangle. The K-wire passes 214 longitudinally through an access aperture1216 of the dilator 1202 and into the spine 100 at the disc space 110.For clarity purposes, additional components and embodiments of thedual-motion rotation and retraction system 1200, including embodimentsof the dilator 1202, the blade assembly 1230, and the dual-motionretractor 1300 in the insertion orientation 239, the rotated orientation306, the closed position 390, and the open position 392, are shownindependent of the patient's body 108. In operation, the components ofthe dual-motion rotation and retraction system 1200 are inserted intoand the rotational and lateral retraction motions occur within the body108 adjacent the patient's spine 100, as shown and discussed in relationto FIGS. 4-31 above.

As discussed above in relation to FIG. 38, embodiments of thedual-motion rotation and retraction system 1200 include a blade assembly1230 having two opposing and identical blade subassemblies 1240 forpositioning opposite either side of the dilator 1202. FIGS. 41A-41Hillustrate perspective, front, rear, left, right, top, and explodedviews of one embodiment of the blade subassembly 1240, respectively. Inthis embodiment, the blade subassembly 1240 includes a conductive blade1244, hingedly bordered by two opposing adjustable wings 1252. In mostaspects, the blade 1244 and the adjustable wings 1252 are similar to theblade 244 a and the wings 252 a, discussed above, in both structure andfunction, including their conductive properties to provide no-wireneuromonitoring capabilities at active monitoring tips 1256 and 1283,respectively, as well as built-in lighting and video capabilities withinthe blade 1244.

In this embodiment, however, the entire combination of the blade 1244and the opposing adjustable wings 1252 may be designed for a single usesuch that they are disposable and selectable based upon patient sizeand/or physiology (e.g., a distance from the disc space 110 to thelateral surface 116 of the patient's body 108 (FIG. 40)). As shown inFIGS. 41F-41H, the disposable blade 1244 and attached wings 1252 may beremovably nested or snapped into a reusable housing 1270 via anattachment phalange 1246 on the blade 1244 that slidable nests within areceiving channel 1248 formed within the housing 1270.

One or more LEDs 1264 and a micro camera 1276 (e.g., a snake-stylecamera) may situated within the blade 1244 and angled as appropriateand/or necessary for optimal viewing (e.g., inward toward the surgicalarea 266 (FIGS. 33-34)). The LEDs 1264 may be battery powered, while thecamera 1276 may be externally powered via a video output/power cable1278 (e.g., an HDMI power cable). As a result, the blade subassembly1240 may feature the smaller, streamlined housing 1270, discussed above,for housing a single battery 1268 accessible via a removeable batterycover 1271. The battery 1268 may be, for example, a lithium coin batteryactuated by a pull tab (not shown), which initiates contact between theinstalled conductive blade 1244 and the battery 1268 to power the one ormore LEDs 1264. In one embodiment, the LEDs 1264 may be continuouslypowered for approximately ten hours once the pull tab is removed. Afteruse, the combination of the disposable blade 1244 and wings 1252, aswell as the battery 1268, may be removed and replaced prior to the nextuse.

In addition and in this embodiment, the opposing adjustable wings 1252may feature a simplified actuation mechanism for rotating the wings 1252inward. In further detail and as shown in FIGS. 41F-41G, the opposingadjustable wings 1252 may be rotated between an open position 1280parallel to the blade 1244, as shown in FIG. 41F, and a closed position1282 in which the wings 1252 are positioned at an inward angle relativeto the blade 1244, as shown in FIG. 41G. This rotational positioning maybe achieved via a cam actuation mechanism that does not require externaltools and/or prolonged applied rotational motion.

As detailed in FIGS. 41F-41G, the cam actuation mechanism may beincorporated into the housing 1270 and may include a cam switch 1284coupled with a rotating slotted cam 1286 having a semi-circular slot1287. A cam pin 1288 may indirectly couple the slotted cam 1286 with alink block 1290 that is slidably nested within the housing 1270. Thelink block 1290 may include a cam end 1291 and a blade end 1292 thatforms a lateral receiving slot 1293. In this regard, the cam pin 1288may protrude from the cam end 1291 of the link block 1290 and throughthe semi-circular slot 1287 of the cam 1286, such that when the camswitch 1284 is rotated, the cam pin 1288 slides along the semi-circularslot 1287 of the cam 1286 and, in turn, displaces the link block 1290 ina rearward direction away from the blade 1244 along arrow D.

To leverage the motion of the link block 1290, each of the adjustablewings 1252 may include a cylindrical protrusion 1294 that, when theblade 1244 and wing 1252 combination is installed onto the housing 1270,protrudes through the lateral receiving slot 1293 of the link block1290. As the link block 1290 moves in the rearward direction of arrow Daway from the blade 1244 in response to rotation of the cam switch 1284,the opposing cylindrical protrusions 1294 of the wings 1254 slideoutward toward the lateral edges of the blade assembly 1240 along ArrowsE, thereby causing each of the wings 1252 to rotate about their hingepins 1249 into the closed position 1282 in the direction of arrows F.Using this cam actuation mechanism, the wings 1252 may be moved betweenthe open and the closed positions 1280, 1282 with the flick of a switch.

The housing 1270 of the blade subassembly 1240 further includes athreaded receiver 1250 positioned at its base. The threaded receiver1250 is adapted for attaching the blade subassembly 1240 to thedual-motion retractor 1300, as shown in FIG. 38 and as discussed furtherbelow in relation to FIGS. 43A-43H.

As discussed above, embodiments of the dual-motion retractor 1300operate to both rotate the dilator 1202 and the blade assembly 1230between the insertion orientation 239 and the rotated orientation 306and to retract the blade subassemblies 1240 away from one another fromthe closed position 390 to the retracted position 392. Thus, thedual-motion retractor 1300 may replace several complex componentsdiscussed above, including the lower coupling device 242, the rotationassembly 312, and the lateral retraction assembly 370 discussed above inrelation to FIGS. 15-28.

Turning to exemplary embodiments of the dual-motion retractor 1300, FIG.42A illustrates a perspective view of one embodiment of the dual-motionretractor 1300 positioned in the insertion orientation 239 and theclosed position 390, while FIG. 42B illustrates the dual-motionretractor 1300 progressed to the rotated orientation 306 and the closedposition 390, and FIG. 42C illustrates the retractor 1300 progressed tothe rotated orientation 306 and the retracted position 392. FIG. 42Dillustrates an exploded view of the dual-motion retractor 1300.

In this embodiment, the dual-motion retractor 1300 includes a retractorbody 1302 that slidably or rotatably retains identical first and secondopposing discs 1304 ₁₋₂. When in the closed position 390, shown in FIGS.42A-42B, the first and second opposing discs 1304 ₁₋₂ form ablade-receiving aperture 1305 configured to receive and retain thedual-blade assembly 1230, as shown in FIG. 38 and discussed below inrelation to FIGS. 43A-43H.

The retractor body 1302 may include a disc support portion 1308 thatforms opposing disc retaining slots 1307 ₁₋₂, each configured toslidably retain the first and the second opposing discs 1304 ₁₋₂,respectively. The retractor body 1302 may further include a handle slideportion 1310. A hollow handle 1306 may be coupled about the handle slideportion 1310 of the retractor body 1302 via a handle sleeve 1312configured to slide along the handle slide portion 1310 with africtional fit such that upon the application of a pushing force or apulling force to the hollow handle 1306, the handle 1306 moves, alongwith the sleeve 1312, along the slide portion 1310 in eitherlongitudinal direction.

A link coupler 1314 may be disposed about the slide portion 1310 of theretractor body 1302 such that at least a portion of the link coupler1314 is disposed between the slide portion 1310 of the body 1302 and thehandle sleeve 1312, thereby causing the link coupler 1314 to move withthe handle 1306 along the slide portion 1310 of the body 1302 in thelongitudinal direction.

A rotative linking mechanism may facilitate both the rotational motionof the first and second opposing discs 1304 ₁₋₂, causing theblade-receiving aperture 1305 to rotate between the insertionorientation 239 and the rotated orientation 306, and the retraction ofthe first and second opposing discs 1304 ₁₋₂ away from one another,causing the blade-receiving aperture 1305 to expand from the closedposition 390 to the retracted position 392.

In greater detail and in reference to FIGS. 42A-42D, a pair of identicalfirst and second short links 1316 ₁₋₂ and a single long link 1318 mayrotatively couple with respective ones of the first and second opposingdiscs 1304 ₁₋₂ and with one another. That is, each of the first and thesecond short links 1316 ₁₋₂ may have a first end 1317 ₁₋₂ and a secondend 1319 ₁₋₂, respectively, and the long link 1318 may have a first end1321 and a second end 1323. The first end 1317 ₁ of first short link1316 ₁ may rotatively couple with the first opposing disc 1304 ₁ via afirst disc hinge pin 1320 ₁, while the first end 1317 ₂ of the secondshort link 1316 ₂ may rotatively couple with the second opposing disc1304 ₂ via a second disc hinge pin 1320 ₂. Both of the second ends 1319₁₋₂ of the first and second short links 1316 ₁₋₂ may be rotativelycoupled with first end 1321 of the long link 1318 via a floating hingepin 1322. The second end 1323 of the long link 1318 may be slidablyinserted within a receiving channel 1324 of the handle slide portion1310 of the retractor body 1302 and rotatively coupled with the linkcoupler 1314 via slider pin 1325.

In this configuration, the dual-motion retractor 1300 is initiallydisposed in a rotation mode in the insertion orientation 239 and theclosed position 390, shown in FIG. 42A. Displacing the handle 1306 inthe direction of Arrow G causes the indirectly coupled second end 1323of the long link 1318 to move proportionately with the handle 1306 inthe direction of Arrow G. This motion simultaneously rotates the firstend 1321 of the long link 1318 about the floating hinge pin 1322 in thedirection of Arrow H and displaces the floating hinge pin 1322 in thedirection of Arrow I, which, in turn, causes the attached second ends1319 ₁₋₂ of the first and second short links 1316 ₁₋₂ to movesimultaneously move with the floating hinge pin 1322 toward the handle1306 in the direction of Arrow I. This displacement of the floatinghinge pin 1322 and the attached second ends 1319 ₁₋₂ of the short links1316 ₁₋₂ displaces the first and second disc hinge pins 1320 ₁₋₂ in thedirection of Arrow I and causes the attached first and second opposingdiscs 1304 ₁₋₂ to move within the disc retaining slots 1307 ₁₋₂ of theretractor body 1302 in the direction of Arrow I, thereby rotating theblade-receiving aperture 1305 from the insertion orientation 239 of FIG.42A to the rotated orientation 306 of FIG. 42B.

From the rotated orientation 306 and closed position 390, the rotativelinking mechanism described above may be switched into a retraction modeand employed to retract the first and second opposing discs 1304 ₁₋₂away from one another into the retracted position 392 of FIG. 42C. Tobegin, a slotted blocking switch 1326 disposed about the handle slideportion 1310 of the retractor body 1302 may be rotated in the directionof Arrow J to transition the dual-motion retractor 1300 into theretraction mode by misaligning an alignment slot 1328 of the slottedblocking switch 1326 and the receiving channel 1324 of the handle slideportion 1310 such that the long link 1318 is selectively retained withinthe channel 1324, as shown in FIG. 42C. Blocking switch 1326 may operatevia electrical, mechanical, or magnetic actuation. Upon rotation of theblocking switch 1326, the handle 1306 may compressed or displaced alongthe handle slide portion 1310 of the retractor body 1302 in thedirection of Arrow K. This displacement also moves the handle sleeve1312 and link coupler 1314 and, in turn, the long link 1318 that iscoupled with the link coupler 1314 via its second end 1323. As the longlink 1318 moves in the direction of Arrow K, both of the first and thesecond short links 1316 ₁₋₂ rotate outward and away from the floatinghinge pin 1322 in the direction of Arrows O, which causes the first ends1317 ₁₋₂ of the first and second short links 1316 ₁₋₂, the rotativelycoupled first and second disc hinge pins 1320 ₁₋₂ and, as a result, theattached first and second opposing discs 1304 ₁₋₂ to move outward andaway from the floating hinge pin 1322 such that the discs 1304 ₁₋₂retract from one another into the retracted position 392 via an outwardforce applied to the first and second disc hinge pins 1320 ₁₋₂, as shownin FIG. 42C.

In one embodiment, each of the first and second opposing discs 1304 ₁₋₂may include a blade port 1330 configured for mating with the threadedreceiver 1250 of blade subassembly 1240 (FIG. 41H). To attach thedual-motion retractor 1300 about the blade assembly 1230, as shown inFIG. 38, two attachment screws 1332 (FIG. 42D) may threadably attach thefirst and second opposing discs 1304 ₁₋₂ to the threaded receivers 1250of the blade subassemblies 1240 via access from the bottom of the bladeports 1330. In addition, the retractor body 1302 may incorporate a tablearm connector port 1334 adapted for securely attaching the dual-motionretractor 1300 to a fixed reference point such as the surgical table 233(FIG. 15) via, for example, a standard tooth jaw and universal jointmechanism (not shown).

Embodiments of dual-motion retractor 1300 and its components may beformed of any appropriate autoclavable or otherwise sterilizable metalor plastic. In one embodiment, the first and second opposing discs 1304₁₋₂ may include any appropriate number of material reducing apertures toreduce one or both the weight and the cost of the dual-motion retractor,while maintaining its ability to be sterilized via autoclave.

FIGS. 40, 43A-43H, and FIGS. 44A-44B generally illustrate a method ofusing embodiments of the disclosed dual-motion rotation and retractionsystem 1200 to employ a lateral surgical approach to clear a surgicalpathway 114 to a patient's spinal disc space 110. Specifically and inone embodiment, FIGS. 43A-43H detail a number of steps in whichexemplary devices are in use to create the surgical pathway 114 throughthe side of the patient's body 108, through, or anterior to, the psoasmuscle 102, and to the intervertebral disc space 110, while FIGS.44A-44B provide a flowchart depicting an exemplary method 1500 ofcreating the surgical pathway 114 through the side of the patient's body108 through, or anterior to, the psoas muscle 102 to the disc space 110.For the purpose of clarity, the surgical table 233, surgical pathway114/surgical area 266, patient's side body 108, psoas muscle 102, andintervertebral disc space 110, which are shown and discussed above inrelation to FIGS. 4-37 and FIG. 40, are not shown in FIGS. 43A-43H.However, embodiments of the dual-motion rotation and retraction system1200 interact with the operating theater and the patient's body in thesame manner as is discussed above.

Dual-motion rotation and retraction system 1200 may be employed forvarious surgical approaches to the spine. Dual-motion rotation andretraction system 1200 may be employed for lateral approach by creatinga surgical pathway through the side of the patient's body through thepsoas muscle, or anterior to the psoas muscle, to an intervertebral discspace where it is possible to dock onto the lateral lumbar disc.Dual-motion rotation and retraction system 1200 may be employed forvariants of the lateral approach, including the “direct lateral”approach in association with the “DLIF” procedure, the “extreme lateral”approach in association with the “XLIF” procedure, the “oblique lumbar”approach in association with the “OLIF” procedure, the “anterior lumbar”approach in association with the “ALIF” procedure, and the “laterallumbar” approach in association with the “LLIF” procedure. Dual-motionrotation and retraction system 1200 may also be employed for a pronelateral trans-psoas or pre-psoas (anterior) approach.

Employing fluoroscopy imaging technology, the dilator 1202 may be placedover/adjacent to the intervertebral disc space 110 (FIG. 43B, 1501).Specifically, and referring to FIG. 40, the dilator 1202 (which may berectangular, elliptical, or any other similar geometrical configuration)may enter through the incision 118 in the patient's side body 108 (FIG.35A, 1502), cut through any intervening fascia (FIG. 44A, 1504), andthen traverse the psoas muscle 102 in a direction, or at the insertionorientation 239, that is “along,” or parallel to the muscle fibers ofthe psoas muscle 102, and diagonal to, or angled at 0 degrees to lessthan 90 degrees to, or in some instances angled at approximately 45degrees to, the patient's spine 100 (FIG. 44A, 1506). The psoas muscle102 may be accessed via the side of the patient's body 108 such that thedilator 202 protrudes from the lateral surface 116 of the patient's body108 when inserted to full depth at the spinal column 100, as shown inthe front perspective view of FIG. 40.

During insertion, impingement of the active monitoring tip 1222 upon, oralternatively, encroachment of the active monitoring tip 1222 in closeproximity to nerve structures located along the patient's spine 100 maystimulate those nerve structures that are nearby or adjacent to theactive monitoring tip 1222. The voltage of the applied electronicstimulus may be adjusted as necessary and/or required to stimulate nervestructures within a defined distance of the active monitoring tip 1222.This applied stimulus causes the nerve structure(s) to fire and generatea responsive signal, which may, in turn, be conducted from the activemonitoring tip 1222, through the conductive electrical pathways of theconductive body 1204, and to the monitoring cable(s) 224 in electroniccommunication with the conductive input surfaces 1207 at the proximalend 1206 of the dilator 1202, as shown in FIG. 40, thereby translatingthe neurosensing stimulation of the active monitoring tip 1222 by thenearby nerve structure(s) to external monitoring equipment (not shown)via the monitoring cable 224 and determining, in real time and with 360degrees of monitoring range or field of view about the distal end 1208of the dilator 1202, a possibility of nerve or plexus injury as thedilator 1202 is inserted (FIG. 44A, 1508).

Once the distal end 1208 of the dilator 1202 is positioned at the spine100 in the insertion orientation 239 that is parallel to the fibers ofthe psoas muscle 102 and spanning the disc space 110 diagonally at anangle of 0 degrees to less than 90 degrees, or in some instances at anapproximate 45-degree angle, the K-wire 214 may be passed longitudinallythrough the access aperture 1216 of the dilator 1202 and into the spine100 at the disc space 110 (FIG. 44A, 1510), both stabilizing andsecuring the position of the dilator 1202, as shown in FIG. 40. Becauseof the active monitoring tip 1222, the full range of monitoring—front toback and superior to inferior—may continue after the dilator 1202 isfixed via the k-wire 214. Unlike previous devices featuring pinpointelectrodes that require manual rotation to perform 360 degrees ofmonitoring, the active monitoring tip 1222 remains active and provides ageometry capable of monitoring in 360 degrees during every stage of itsinsertion and use during a procedure.

Referring to FIGS. 43A-43C, after securing the K-wire 214 (FIG. 44A,1510) into the disc space 110 of the spine 100 such that the dilator1202 is stabilized, secured, and providing continuous neuromonitoring(FIG. 40) (FIG. 44A, 1508), the dual blade assembly 1230 may be inserteddistally-to-proximally, in the direction of Arrow L, into theblade-receiving aperture 1305 of the dual-motion retractor 1300 andsecured via the mated blade ports 1330 of the dual-motion retractor 1300and the threaded receivers 1250 of the dual blade assembly 1230 (FIG.44A, 1512).

The dual blade assembly 1230, as assembled into the dual-motionretractor 1300, may then be passed at the insertion orientation 239 andin the direction of Arrow L over and alongside the installed dilator1202, as shown in FIGS. 43B-43C, such that each blade 1244 of thedual-blade assembly 1230 opposes and contacts one of the opposing outersurfaces 1211 of the dilator 1202 (FIG. 44A, 1514) to further minimizedamage to nerve structures and muscle fibers while providing continuous,360-degree nerve monitoring about the distal ends of the blades 1244(FIG. 44A, 1516). After appropriate alignment in the insertionorientation 239 is achieved, the dual-motion retractor 1300 may besecured to the surgical table 233 (FIG. 15) or another appropriatestabilizing surface within the operating theater in any appropriatemanner (FIG. 44A, 1518).

Next, and in reference to FIGS. 43C-43E, the rotative linking mechanismof the dual-motion retractor 1300 may be actuated to rotate thedual-blade assembly 1230 and the dilator 1202 about the K-wire 214 by anangle of 0 degrees to less than 90 degrees, or in some instances atapproximately 45-50 degrees, in the direction of arrow I, from theinitial insertion orientation 239 parallel to the fibers of the psoasmuscle 102, as shown in FIG. 43C, to the final rotated orientation 306parallel to the disc space 110 in which the blades 1244 of thedual-blade assembly 1230 are positioned transverse to the fibers of thepsoas muscle 102 and begin to separate the fibers of the psoas muscle102, as shown in FIG. 43E (FIG. 44B, 1520). FIG. 43D illustrates a topplan view of the dual-motion rotation and retraction system 1200 atmid-transition between the insertion orientation 239 of FIG. 43C and thefinal rotated orientation 306 of FIG. 43E. As detailed above in relationto FIGS. 42A-42B, rotation from the insertion orientation 239 to therotated orientation 306 is accomplished by manually pulling the handle1306 of the retractor body 1302 rearward in the direction of Arrow G(FIG. 44B, 1522).

Once oriented in the rotated orientation 306, as shown in FIG. 43E, therotative linking mechanism of dual-motion retractor 1300 may again beactuated to retract the first and second opposing discs 1304 ₁₋₂ of theretractor 1300, and thus the attached blade subassemblies 1240, from theclosed position 390 in which the blades 1244 of the blade subassemblies1240 abut the dilator 1202, as shown in FIGS. 43E-43F, to the retractedposition 392 in which the blade subassemblies 1240 are retracted outwardaway from the dilator 1202, as shown in FIG. 43G (FIG. 44B, 1524). Toaccomplish this retraction motion, and as detailed above in relation toFIGS. 42B-42C, the slotted blocking switch 1326 of the retractor 1300may be rotated in the direction of Arrow J to misalign the alignmentslot 1328 of the slotted blocking switch 1326 and the receiving channel1324 of the handle slide portion 1310 of the retractor 1300, such thatthe long link 1318 is retained within the receiving channel 1324 of thehandle slide portion 1310 of the retractor body 1302, as shown in FIG.43F (FIG. 44B, 1526). Then the handle 1306 may be displaced or returnedin the forward direction along the handle slide portion 1310 in thedirection of Arrow K to retract the opposing discs 1304 ₁₋₂ and, inturn, retract the blade subassemblies 1240 attached to the discs 1304₁₋₂ from one another, as shown in FIG. 43G (FIG. 44B, 1528). Onceretraction is complete, the dilator 1202 may be removed by displacing itin the direction of Arrow M to clear the surgical pathway 114, as shownin FIG. 43H (FIG. 44B, 1530), and, as detailed above in relation toFIGS. 41F-41G, the opposing adjustable wings 1252 of the blades 1244 ofthe blade subassemblies 1240 may be adjusted between the open position1280 and the closed position 1282, as necessary and/or required toprevent creep into the surgical pathway 114 and/or manage reflectionfrom the lighting and/or cameras (FIG. 44B, 1532), enabling the surgeonaccess to the surgical site via the surgical pathway 114 (FIG. 44B,1536).

Throughout the steps of rotating the dual-blade assembly 1230 from theinsertion orientation 239 to the rotated orientation 306 (FIG. 44B,1520), laterally retracting the blade subassemblies 1240 from the closedposition 390 to the retracted position 392 (FIG. 44B, 1524), andadjusting the adjustable wings 1252 between the open position 1280 andthe closed position 1282 (FIG. 44B, 1532), the active monitoring tips1256 and 1283 of the blades 1244 and the wings 1252, respectively, maybe used to provide real-time neuromonitoring to prevent impingementand/or encroachment upon adjacent nerve structures (FIG. 44B, 1534).

Embodiments of the dual-motion rotation and retraction system 1200,including the dual-motion retractor 1300, the dual blade assembly 1230,and the dilator 1202, provide three separate types of movement—rotationof the dilator 1202 and the dual-blade assembly 1230 from the insertionorientation 239 to the final rotated orientation 306, retraction of theblade subassemblies 1240 from the closed position 390 to the retractedposition 392, and rotation of the adjustable wings 1252 from the openposition 1280 to the closed position 1282—that allow for sophisticatedinitial placement of the single-component dilator 1202 and thedual-blade assembly 1230 in a manner parallel to, or anterior to, thepsoas muscle 102 and, therefore, less damaging to the muscle and nervestructures adjacent to the patient's spine. Further, the simplifieddual-motion retractor 1300 provides for the rotational movement of thedilator 1202 and the dual blade assembly 1230, as well as the lateralretraction of the blade subassemblies 1240 of dual blade assembly 1230,via a simple, elegant design that replaces the lower coupling device242, the rotation assembly 312, and the lateral retraction assembly 370discussed above in relation to at least FIGS. 9-10, 15-28. Thedual-motion retractor 1300 is compact, intuitive to use in the surgicalsetting, fully autoclavable, and inexpensive to manufacture.

Embodiments of the dual-motion rotation and retraction system 1200,including the dual-motion retractor 1300, the dual blade assembly 1230,and the dilator 1202, may further include a robotic navigation platformproviding one or both of robotic arm movement and navigationimplementing virtual tracking. For example, the platform may combine arigid robotic arm and full navigation capabilities for accuratetrajectory alignment in connection with dilation and retraction.Advantageously, the robotic navigation platform in operable combinationwith the dual-motion rotation and retraction system provide virtualtracking relative to the patient and optimized control of the dilatorand dual blade assembly based on this virtual tracking. This control mayinclude one or more of positioning, rotation and opening of the dilatoror dual-motion retractor, which provides enhanced safety and improvedefficiency for patients and medical personnel.

In various embodiments, the robotic navigation platform may include atwist lock arm to allow the robotic navigation platform to provide all,or at least a portion of, the placement, retraction, and turning of oneor both of the dilator and the dual-motion retractor. Artificialintelligence (AI) may be employed for placement and operation of one orboth of the dilator and the dual-motion retractor relative to thesurgical site. The robotic navigation platform may include fiducialoptical trackers for guidance. These may include one or more ofpre-operational scans, interoperative scan, and real-time surgeonguidance. Laser technologies as well as future developed tracking andguidance systems may be employed by the robotic navigation platform forpositioning, rotation and opening of the dilator or dual-motionretractor.

In one embodiments, the robotic navigation platform may include guidanceof the robotic navigation platform through one or both of cable orwireless, non-cable, communication networks. Traditional cable, fiberoptic, coaxial, twisted pair, wireless, radiofrequency (RF), microwavetransmission, light wave, infrared, WIFI, and Bluetooth communicationsare exemplary communication tools that may be employed by the roboticnavigation platform for positioning, rotation and opening of the dilatoror dual-motion retractor in the trans-psoas or the pre-psoas arena.

In an embodiment, the robotic navigation platform may provide virtualtracking and related information with respect to positioning of thedual-motion rotation and retraction system relative to a patient, theplatform provides the benefit of enhanced control relative to thesurgical operations. For example, the dilator may be controlled with arobotic arm and navigational fiducials to a precise initial locationrelative to the patient, an optimal rotation relative to the psoasmuscle, and an optimal depth of placement relative to the surgicallocation. Similarly, the dual-motion retractor may be controlled withthe robotic arm and navigational fiducials to a precise location,rotation, placement, and opening distance. This enhanced control mayalso include the robotic navigation platforming neuromonitoring duringone or both of placement of the dilator and placement and opening of thedual-motion retractor.

Although the above embodiments have been described in language that isspecific to certain structures, elements, compositions, andmethodological steps, it is to be understood that the technology definedin the appended claims is not necessarily limited to the specificstructures, elements, compositions and/or steps described. Rather, thespecific aspects and steps are described as forms of implementing theclaimed technology. Since many embodiments of the technology can bepracticed without departing from the spirit and scope of the invention,the invention resides in the claims hereinafter appended.

1-22. (canceled)
 23. A method of forming a surgical pathway through aside of a patient's body and through a psoas muscle to an intervertebraldisc space, comprising: providing a dilator having a narrow body definedby opposing surfaces extending between tapered opposing longitudinaledges; positioning the dilator at an insertion orientation in which theopposing surfaces extending between the tapered opposing longitudinaledges of the dilator are disposed parallel to a direction of a pluralityof fibers of the psoas muscle; traversing the plurality of fibers of thepsoas muscle until the dilator spans the intervertebral disc space atthe insertion orientation in which the opposing surfaces extendingbetween the tapered opposing longitudinal edges of the dilator aredisposed parallel to the plurality of the fibers of the psoas muscle andat an angle of approximately 45 degrees to the intervertebral discspace.
 24. The method of claim 23, further comprising: via a k-wireextending longitudinally through a center of the dilator, securing thedilator within the intervertebral disc space at the insertionorientation.
 25. The method of claim 23, further comprising: providing adual-blade assembly consisting of a pair of opposing blades, each havingan inner surface and an opposing outer surface that extend from aproximal end to a distal end along two longitudinal sides; and passingthe dual-blade assembly proximally-to-distally over the dilator at theinsertion orientation such that the inner surface of each of theopposing blades contacts one of the opposing surfaces extending betweenthe tapered opposing longitudinal edges of the dilator.
 26. The methodof claim 25, further comprising: rotating, via a rotation assemblyoperably coupled to the dual-blade assembly, the dilator and thedual-blade assembly about the k-wire from the insertion orientation to arotated orientation in which the opposing surfaces extending between thetapered opposing longitudinal edges of the dilator and the innersurfaces of the opposing blades are disposed parallel to theintervertebral disc space.
 27. The method of claim 26, furthercomprising: retracting, via a lateral retraction assembly operablycoupled to the dual-blade assembly, the pair of the opposing bladesapart from one another to form the surgical pathway.
 28. The method ofclaim 27, wherein a wing is hingedly coupled with each of thelongitudinal sides of each of the opposing blades, the method furthercomprising: rotating the wing from an open position parallel to theinner surface of the blade to which the wing is coupled to a closedposition perpendicular to the inner surface of the blade to which thewing is coupled.
 29. The method of claim 27, further comprising: duringthe step of traversing the plurality of the fibers of the psoas muscle,using a first active monitoring tip formed adjacent to the distal edgeof the dilator to continuously and simultaneously detect an impingementof the dilator upon one or more nerve structures located adjacent to anyportion in 360 degrees of a circumference of the distal end of thedilator.
 30. The method of claim 27, further comprising: during thesteps of passing the dual-blade assembly proximally-to-distally over thedilator, rotating the dilator and the dual-blade assembly about thek-wire from the insertion orientation to the rotated orientation, andretracting the pair of the opposing blades apart from one another, usinga second active monitoring tip formed adjacent to the outer surface ofthe distal end of each of the pair of the opposing blades tosimultaneously and continuously sense an impingement of the dual-bladeassembly upon one or more nerve structures located adjacent to 360degrees of the outer surfaces of the blades.
 31. The method of claim 27,further comprising: activating one or more light emitting diodes (LEDs)built into each of the opposing blades to illuminate the surgicalpathway.
 32. The method of claim 27, further comprising: activating avideo camera built into one or both of the opposing blades to captureone or more video streams from within the surgical pathway.
 33. Themethod of claim 23, further comprising: rotating the dilator about thek-wire from the insertion orientation to a rotated orientation in whichthe opposing surfaces extending between the tapered opposinglongitudinal edges of the dilator are disposed parallel to theintervertebral disc space.
 34. A method of creating a surgical pathwayto a patient's spine using a lateral retractor system including adilator having a tapered cross-section between opposing longitudinaledges, a retractable blade assembly including two opposing blades thateach taper to a distal edge, a rotation assembly operably coupled withthe retractable blade assembly, and a retraction assembly operablycoupled with the retractable blade assembly, the method comprising:inserting the dilator through a psoas muscle of the patient such thatthe dilator spans an intervertebral disc space at an insertionorientation that is parallel to a plurality of fibers of the psoasmuscle; using a k-wire extending longitudinally through a center of thedilator, anchoring the dilator at the intervertebral disc space; androtating the dilator about the k-wire from the insertion orientationthat is parallel to the psoas muscle to a rotated orientation that isparallel to the intervertebral disc space.
 35. The method of claim 34,further comprising: during the steps of inserting, anchoring, androtating the dilator, and using a first active neuromonitoring tippositioned adjacent to the distal edge of the dilator, monitoringcontinuously and simultaneously for an encroachment upon one or morenerve structures of the patient located adjacent to any portion in 360degrees of a circumference of the first active neuromonitoring tip. 36.The method of claim 34, wherein the inserting the dilator comprisesusing the distal edge of the dilator to traverse the one or more of thefibers of the psoas muscle without cutting or compressing the one ormore of the fibers of the psoas muscle.
 37. The method of claim 34,wherein the first active monitoring tip comprises: a series ofhorizontal sensing wires embedded within the dilator adjacent to thedistal edge of the dilator; and at least one conducting wire extendinglongitudinally through the dilator, the at least one conducting wireelectrically coupled with the series of the horizontal sensing wires.38. The method of claim 34, further comprising: prior to the step ofrotating the dilator about the k-wire, passing the retractable bladeassembly proximally-to-distally over the dilator at the insertionorientation such that an inner surface of each of the two opposingblades contacts the dilator; and coupling the rotation assembly to theretractable blade assembly such that the step of rotating the dilatorabout the k-wire comprises: using the rotation assembly, rotating thedilator and the retractable blade assembly about the k-wire from theinsertion orientation to the rotated orientation.
 39. The method ofclaim 38, further comprising: during the steps of passing theretractable blade assembly proximally-to-distally over the dilator,rotating the dilator and the retractable blade assembly about the k-wirefrom the insertion orientation to the rotated orientation, andseparating the two opposing blades of the retractable blade assemblyapart from one another, using a second active neuromonitoring tippositioned adjacent the distal edge of each of the two opposing bladesto monitor for an encroachment upon one or more nerve structures of thepatient located adjacent to an outer circumference of a distal end ofthe retractable blade assembly.
 40. The method of claim 39, wherein:during the steps of passing the retractable blade assemblyproximally-to-distally over the dilator, rotating the dilator and theretractable blade assembly about the k-wire from the insertionorientation to the rotated orientation, separating the two opposingblades of the retractable blade assembly apart from one another, androtating the adjustable wing between the open position and the closedposition, using a third active neuromonitoring tip positioned adjacentto a distal edge of each of the adjustable wings to monitor for anencroachment upon one or more nerve structures of the patient locatedadjacent to an outer circumference of a distal end of the retractableblade assembly.
 41. The method of claim 34, further comprising: couplingthe retraction assembly to the retractable blade assembly; and using theretraction assembly, separating the two opposing blades of theretractable blade assembly apart from one another.
 42. The method ofclaim 41, wherein the retractable blade assembly further comprises anadjustable wing hingedly coupled with each of two longitudinal sidesalong each of the two opposing blades, the method further comprising:rotating the adjustable wing between an open position in which theadjustable wing extends parallel to an attached one of the two opposingblades and a closed position in which the adjustable wing extendsperpendicular to the attached one of the two opposing blades.